A lesbian from the area of San Francisco. 'Frisco is an abbreviation for San Francisco, thus a 'Frisco dyke is one of the members of the massive gay/lesbian community coming from that part of the West Coast. Snoop Dogg uses it in a rap dissing Easy-E (both rappers were born and live in that area of the United States).

'It seems like you're good for makin jokes about your jimmy,
But here's a jimmy joke about your mama that you might not like,
I heard she was a 'Frisco dyke.'
Snoop Dogg, Fuck Wit Dre Day (And Everybody's Celebrating)